Biomedical subjects

K Liu

Publications and source records attributed to K Liu.

At least 199 records · Page 11Linked to original sources

PubMed1999

Primary central nervous system lymphomas: a 30-year experience at a single institution.

Primary central nervous system lymphoma (PCNSL) is a rare disease that has been increasing in frequency. Clinical, histologic, and immunohistochemical data from 64 cases of PCNSL seen at Duke University Medical Center since 1968 were reviewed and tumors were classified using the REAL classification system. Thirty-two patients were male and 32 were female, with a mean age of 57.1 years, ranging from 16 to 82 years. Large B-cell lymphoma represented overwhelming the majority of PCNSL, accounting for 81% of all cases. Phenotypic T-cell lymphomas were rare with only two cases over the course of the study. Epstein-Barr virus was detected only in the immunocompromised patients and was identified in 75% of those immunocompromised patients who were tested. Overall survival was poor with a mean survival of 357 days and median survival of 158 days. One- and three-year survival rates were 29.6% and 7.8%, respectively. Type of treatment, duration of symptoms, site of lesion, and histologic subtype were not significant prognostic indicators, whereas concurrent immunosuppression was the strongest predictor of poor outcome. In AIDS patients (which accounted for 21.9% of the study group), the median survival was 65 days, which was significantly different than that seen in the immunocompetent group of 217 days (P = .001).

Adolescent↗

PubMed1999

[DNA vaccination of the induction of immune responses by codelivery of IL-12 expression vector with hepatitis C structural antigens].

OBJECTIVE: In an attempt to demonstrate the utility of DNA vaccines for the tailored methods, the efficacy of immune responses would be enhanced and the types of immune responses shifted. METHODS: Four recombinant plasmids were constructed. These included the HCV coding regions for the core protein(pC) and for the core E1 and E2 together(pCE1E2) IL-12 p35 and p40. These plasmids were transfected into mammalian cells to test their protein expression and were injected into the quadriceps muscles of BALB/C mice to measure specific antibodies and cytotoxic T-lymphocyte responses. RESULTS: All the recombinant plasmids were shown to express specific antigens in cells transiently and stably. Codelivery of pIL-12 expression cassettes with pC and pCE1E2 in mice resulted in splenomegaly and the increasing number of the splenocytes. It also resulted in the enhancement of Ag-dependent CTL responses and the reduction of specific Ab response. The CTL activity were pC = 18.65% +/- 5.71%, pCE1E2 = 20.07% +/- 11.11%, pC + pIL-12 = 60.11% +/- 17.37%, pCE1E2 + pIL-12 = 67.48% +/- 15.57%, respectively. The Anti-HCV activity were pC = 0.415 +/- 0.127, pCE1E2 = 0.358 +/- 0.096, pC + pIL-12 = 0.210 +/- 0.086, pCE1E2 + pIL-12 = 0.258 +/- 0.125, respectively. CONCLUSION: Codelivery of pIL-12 with plasmid DNA can enhance the efficacy of immune responses and shift the type of immune responses. This work demonstrates the power of DNA delivery in vivo for both the production of a new generation of more effective and targeted vaccines or immuno-therapies as well as an analytic tool for the molecular dissection of the mechanisms of immune function.

Animals↗

PubMed1999

[Detection of tumor cells in peripheral blood for patients with ovarian epithelial carcinoma].

OBJECTIVE: To detect tumor cell contamination of peripheral blood stem cell (PBSC) and the presence of tumor cells in peripheral circulating blood in patients with primary advanced ovarian cancer. METHODS: To establish limits of sensitivity of the immunocytochemical stainings technique (ABC method) for tumor cell detection, four types of ovarian cancer tumor cell(ovarian cancer cell lines SKOV3, 3AO, primary cancer cell from ascites of serous papillary carcinoma and undifferentiated adenocarcinoma) were added into normal blood to prepare the models with different ratios of tumor cells to mononuclear cells. Monoclonal antibodies(MAB) of COC 183 B2, CK(AE1/AE3) and their cocktail antibody (mixture of them) were used for immunocytochemical stainings. 14 blood specimens were examined (6 stem cell blood specimens, 8 primary advanced ovarian cancer blood spcimens). RESULTS: The sensitivity of detection achieved by cocktail antibodies was superior to either COC183B2 or CK MAb alone. The sensitivity of cocktail antibody was 1:5 x 10(5). According to the established sensitivity, none of the fourteen specimens contained tumor cell. CONCLUSIONS: None of the 6 PBSC specimens obtained from 2 patients and eight peripheral blood specimens obtained from 8 patients with primary ovarian epithelial carcinoma contained tumor cell.

Adenocarcinoma↗

PubMed1999

Surgical treatment of hepatocellular carcinoma and related basic research with special reference to recurrence and metastasis.

OBJECTIVE: To summarize the progress of surgical treatment of hepatocellular carcinoma (HCC) and related basic research at the Liver Cancer Institute of Shanghai Medical University in the recent years, with special reference to recurrence and metastasis. METHODS: Published and unpublished update clinical and experimental data in the above-mentioned areas are summarized. RESULTS: Surgical resection has played an important role in improving prognosis of HCC, the 5-year survival were 63.4% for small HCC resection (n = 806), 39.6% for large HCC resection (n = 1061), 64.7% for cytoreduction (using hepatic artery cannulation and ligation) and sequential resection of initially unresectable HCC (n = 93), 56.0% for cytoreduction using transcatheter arterial chemoembolization (TACE) and followed by resection (n = 65), and 22.4% for hepatic resection with removal of tumor thrombi in portal vein (n = 103). Unfortunately, the 5-year recurrent rate after curative resection of HCC was up to 61.5%, which was mainly a result of intrahepatic "metastasis" and multicentric origin of HCC. Clinically, re-resection of subclinical recurrence yielded 56% of 5-year survival (n = 202); prevention of recurrence by transcatheter arterial chemoembolization (TACE) + Interferon, or LAK/IL-2 therapy have decreased 3-year recurrent rate from 33% to 11%-18%. In experimental aspect, metastatic human HCC model in nude mice (LCI-D20) and HCC cell line with metastatic potential (MHCC97) have been established; studies on HCC invasiveness in the molecular level revealed similar results that reported in other solid cancers, and small HCC showed slightly better biological characteristics as compared with large HCC; microvessel density (MVD) that reflecting angiogenesis adversely correlated with 5-year survival of small HCC; experimental interventions using antisense H-ras, bispecific antibody, BB94, as well as anti-angiogenic agents (TNP470, suramin, CAI, heparin, antisense VEGF, etc.) have been demonstrated to inhibit tumor growth and lung metastasis in nude mice model. CONCLUSIONS: Recurrence and metastasis are the major obstacle to further improve prognosis of HCC, studies should be conducted both in clinical and experimental aspects, "HCC invasiveness" will be the major target to be studied, particularly in the molecular level, and anti-angiogenesis will be one of the important approach.

Angiogenesis Inhibitors↗

PubMed1999

Effect of immunization in mice with recombinant DNA encoding the hepatitis C virus structural protein.

OBJECTIVE: To explore the possibility and the efficacy of immune responses in mice inoculated with recombinant plasmid pCD-HCV1 and to lay a foundation for HCV nucleic acid vaccine development in the future. METHODS: The gene fragment coding C and E regions of HCV-II (type I b) was inserted into pCD-SR alpha 1 expression vector and formed pCD-HCV1 and then was injected into quadriceps muscles of Balb/c mouse. Serum anti-HCV level of mice was tested by ELISA (A value). Spleen cells proliferation responses to HCV antigens were detected by 3H-TdR incorporation (cpm). RESULTS: Balb/c mice immunized with recombinant plasmid pCD-HCV1 three or four times can generate specific antibody responses to HCV antigens and the antibody levels gradually ascend to the plateaus and did not have the trend of descending in 18 weeks detected. The serum antibodies in mice immunized by recombinant plasmid pCD-HCV1 were 100 percent positive when the serum were diluted 40 times and the positive rate of antibody still were 16.6 percent positive when the serum were diluted 320 times. Balb/c mice immunized with recombinant plasmid pCD-HCV1 (100 micrograms, 50 micrograms 10 micrograms/mouse three times respectively) can elicit antibody responses to HCV antigens and the antibody levels of three groups were 0.70 +/- 0.07, 0.33 +/- 0.04 and 0.11 +/- 0.09 respectively. Spleen cells of Blab/c mice injected with pCD-HCV1 three times were induced to produce proliferation responses to HCVc + e specific antigens. CONCLUSIONS: These results demonstrated that constructs expressioning HCV core and envelope proteins can generate anti-HCVc + e specific antibody responses and lymphoproliferation responses in mice, which suggested it to be possible to elicit immune responses to viral epitopes from HCV via DNA immunization with HCV-DNA recombinant and to warrant further investigation as a potential vaccine against HCV infections.

Animals↗

PubMed1999

[Preliminary study on the antitumor immuno-protective mechanism of beta-elemene].

OBJECTIVE: To study the antitumor effects and their molecular mechanism of beta-elemene, which is one of the effective monomers of Oleum Curcuma aromatica, a Chinese anticancer medicament. METHODS: The expression of membrane protein HSP70 on H22 cells treated with beta-elemene or mitomycin C(MMC) was analysed by immunofluorescence and flow cytometric techniques and the antitumor effects of the treated H22 cells was examined in C57BL/6 mice. RESULTS: The expression rate or intensity of membrane protein HSP70 of H22 cells treated with beta-elemene, and those treated with MMC was both significantly higher than that of the untreated H22 cells (P < 0.001). Increase in HSP70 expression was most marked when H22 cells were treated with beta-elemene and MMC in combination, with an expression rate of 95.1%. Heat shock treatment of the H22 cells combined with other stress-inducing factors could further increase the HSP70 expression intensity. Specific antitumor immunity could be elicited in C57BL/6 mice immunized with beta-elemene-treated H22 cells, and the effect could be partially blocked by anti-HSP70 mAb. In mice immunized with beta-elemene-treated H22 cells, tumor developed in 3 of 11 mice, while in the immunized mice given anti-HSP70 mAb, 5 out of 10 mice developed tumor, and all of the control mice developed tumor. The average tumor weight (g) on day 28 after challenge with untreated H22 cells was 0.17 +/- 0.33, 0.66 +/- 0.77 and 1.11 +/- 0.58 in the three groups of mice, respectively. CONCLUSION: beta-elemene increases tumor cell immunogenicity by inducing, at least in part, elevated expression of heat shock protein 70 on tumor cell surface.

Animals↗

PubMed1999

[Experimental study of immunization of mice with hepatitis C virus genetic vaccine constructs].

OBJECTIVE: To inquire into the immune responses to expression protein in mice immunized with genetic vaccine of hepatitis C virus (HCV) and lay a foundation for HCV genetic vaccine development in future. METHODS: The gene fragments coding C and most E regions of HCV-II type were inserted into pCD-SRalpha(1) of eukaryotic expression vector and formed genetic vaccine constructs of pCD-HCV(1) and then was injected into the quadriceps muscles of Balb/c mice. The serum anti-HCV level of mice was tested by ELISA and peripheral blood mononuclear cell (PBMC) proliferative responses to HCV antigens were detected by (3)H-TdR incorporation method (cpm). RESULTS: The serum antibody level reached to 0.71 +/- 0.08 - 0.77 +/- 0.06 (A value, the same below) after genetic vaccine pCD-HCV(1) (100 microg/mouse) were inoculated into the mice (n = 12) three or four times while blank vector pCD-SRalpha(1) could not induce the mice (n = 8) to generate antibody response in same way. After the antibody levels in mice (n = 8) immunized by pCD-HCV(1) had ascended to peak value (0.71), there was no trend of descending during the following 18 weeks of detection (0.68 +/- 0.06 - 0.75 +/- 0.07). Specific fragment of HCV cDNA identified by polymerase chain reaction (PCR) from DNA extracted from the muscles of the mice after pCD-HCV(1) had been inoculated three months. PBMC proliferative responses to HCV synthetic peptides CP(9) and gene recombinant antigens C, E(1) in the mice immunized with pCD-HCV(1) were detected and its stimulation indexes (SI) were 4.07 +/- 1.58, 3.88 +/- 0.70 and 3.69 +/- 1.13 respectively and there was a significant difference (P < 0.001) as compared with that of PBMC in mice immunized with pCD-SRalpha(1). CONCLUSION: These investigations demonstrated that genetic vaccine constructs made of HCV structural region can induce Balb/c mice to generate antibody and PBMC proliferative responses to HCV antigens via DNA immunization.

Animals↗

PubMed1999

[An analysis of nutritional and harmful components of vegetables grown in plastic greenhouses].

OBJECTIVE: To study the changes in nutritional and harmful components of vegetables grown in plastic greenhouses. METHODS: In plastic greenhouses, microclimate and air concentrations of carbon monoxide, carbon dioxide, fluoride and respirable particulate were measured, and chlorophyll, total sugar, crude fiber, nitrite, fluoride, arsenic and some mineral elements in vegetables were determined as compared with those grown in the open-air fields. RESULTS: Greenhouse appeared a lower wind speed and darker illumination. Contents of chlorophyll a an b, total chlorophyll, reduced vitamin C, crude fiber in vegetables grown in greenhouse all were lower than those grown in open-air fields. Contents of potassium, calcium, magnesium, iron, zinc, copper and phosphorous were all lower in the vegetables grown in greenhouse than those grown in open-air fields. The contents of chlorophyll reducing Vitamin C. CONCLUSION: Lower wind speed and inadequate illumination in greenhouse affected photosynthesis and uptake of water in vegetables causing changes in their nutritional components. But, no contamination of burning coal was found in vegetables grown in greenhouse.

Air Pollutants↗

PubMed1999

[Review on transforming growth factor beta and repair of tissue injury].

OBJECTIVE: To review the progress of the relation between transforming growth factor beta (TGF-beta) and repair of tissue injury. METHODS: The recent articles about TGF-beta and tissue reconstruction were extensively reviewed. The gene identification, production, activation of TGF-beta and its role in the repair course of tissue injury were investigated. RESULTS: TGF-beta belongs to a family of multifunctional polypeptides, its gene structure is highly conservative. Many animal models about TGF-beta and tissue injury have been established. The research mainly focuses on the classification, distribution of TGF-beta receptors and their signal pathway. CONCLUSION: TGF-beta plays an important roles in the regulation of repair of tissue injury.

Animals↗

PubMed1999

[Pharmacological comparison between volatile oil and water extract].

OBJECTIVE: To compare the pharmacological differences between volatile oil and water extract in eight aromatic drugs for resolving dampness. METHOD: Volatile oil and water extract of eight commonly used aromatic drugs for resolving dampness were ig administered to rats respectively, and the effects of volatile oil and water extract on the secretion of gastric juice, volume of gastric mucous blood flow and activity of SOD in gastric mucous membrane were studied. RESULT: It was shown that the effects of aromatic volatile oil in eight drugs on the indexes mentioned above were generally equal or similar to those of water extract, and it was obvious that the volatile oil in some high oil content drugs such as Amonum cardamomum L(Baidoukou), Alpinia katsumadai Hagata (Caodoukou), Amomum villosum Lour (Saren), and Amomum tsao-ko Crevost et Lem (Caogou) had better effects on the secretion of gastric juice and volume of gastric mucous blood flow that those of water extract. CONCLUSION: It has been pharmacologically proved that in using aromatic drugs for resolving dampness, the loss of aromatic (volatile) components should be avoided.

Animals↗

PubMed1999

[The determination of anions of very weak acids by incompletely suppressed conductometric detection].

A novel method, incompletely suppressed conductometric detection, has been developed for the determination of anions of very weak acids. The principle of the method is discussed. The advantages of the method over the suppressed and nonsupressed methods for the determination of anions of very weak acids are also discussed theoretically. Results showed that the detection limits of the method for arsenous acid and boric acid were lower than those of nonsuppressed conductometric method. Being compared with suppressed conductometric method, the sensitivity was improved greatly. For 250 mg/L boric acid, 261- and 1002-fold increases in peak height and peak area were obtained, respectively. Within the linear range of the detection, the linear correlation coefficients of the peak areas of two weak acids were 0.9991 and 0.9985, respectively.

Anions↗

PubMed1999

[Liquid chromatography with amperometric detection].

Amperometric detection in liquid chromatography is introduced in this article. Detection mechanism and conditions involved in the application in HPLC and HPIC with d.c. amperometry, pulsed amperometry and integrated amperometry detection are discussed.

Chromatography, High Pressure Liquid↗

PubMed1999

[TXRF technique and quantitative analysis of mollusc teeth].

Total reflection X-ray fluorescence (TXRF) analysis technique and the instrument with a short path, high efficiency, low power and small volume are briefly presented. The detection limit of the system are at pg-level for Cu and Mo target excitation. Teeth of a marine mollusc were measured quantitatively and the spectrum and analysis results were given.

Animals↗

PubMed1998

[Development of an in vitro model of culture using mouse fetal long bone].

An in vitro model of culture using mouse fetal long bone was firstly established using self-made turning-equipment. The bone formation, mineralization and resorption were observed simultaneously in cultured bone. It provided a useful model for investigating the relationship between bone, development and the effect of nutrients, toxicants and other factors.

Animals↗

PubMed1998

Association of apolipoprotein E phenotype with plasma lipoproteins in African-American and white young adults. The CARDIA Study. Coronary Artery Risk Development in Young Adults.

Apolipoprotein E phenotype (APOE phenotype) has been demonstrated to be a genetic determinant of cardiovascular disease. This atherogenicity may be a reflection of the association of APOE phenotype and plasma lipoprotein concentrations. The Coronary Artery Risk Development in Young Adults (CARDIA) Study affords the opportunity to assess the frequency of apolipoprotein E alleles in population-based samples of African Americans and whites in the United States and to compare the associations of APOE phenotype with lipoprotein and apoprotein concentrations. Data from 3,485 African-American and white men and women between the ages of 25 and 37 years who attended the fourth CARDIA Study examination in 1992-1993 were used in this analysis. African-American men and women had significantly higher frequencies of E2 and E4 phenotype and thus higher frequencies of *epsilon2 and *epsilon4 alleles (p < 0.005). Men and women of both races with APOE4 phenotype generally had higher low density lipoprotein cholesterol, apolipoprotein B, and lipoprotein(a) concentrations and lower high density lipoprotein cholesterol concentration, and individuals with APOE3 phenotype had the lowest triglyceride concentration. Major differences between African Americans and whites were observed in the distribution of APOE phenotypes and *epsilon alleles, but APOE phenotype was associated with similar differences in lipoprotein and apoprotein concentrations in both races. The data suggest that APOE phenotype may be a risk factor for cardiovascular disease in both African Americans and whites because it is associated similarly with an adverse lipoprotein profile.

Adolescent↗

PubMed1998

Benefit of a favorable cardiovascular risk-factor profile in middle age with respect to Medicare costs.

BACKGROUND: People without major risk factors for cardiovascular disease in middle age live longer than those with unfavorable risk-factor profiles. It is not known whether such low-risk status also results in lower expenditures for medical care at older ages. We used data from the Chicago Heart Association Detection Project in Industry to assess the relation of a low risk of cardiovascular disease in middle age to Medicare expenditures later in life. METHODS: We studied 7039 men and 6757 women who were 40 to 64 years of age when surveyed between 1967 and 1973 and who survived to have at least two years of Medicare coverage in 1984 through 1994. Men and women classified as being at low risk for cardiovascular disease were those who had the following characteristics at the time they were initially surveyed: serum cholesterol level, <200 mg per deciliter (5.2 mmol per liter); blood pressure, < or =120/80 mm Hg; no current smoking; an absence of electrocardiographic abnormalities; no history of diabetes; and no history of myocardial infarction. We compared Medicare costs for the 279 men (4.0 percent) and 298 women (4.4 percent) who had this low-risk profile with those for the rest of the study group, who were not at low risk. Health Care Financing Administration charges for services to Medicare beneficiaries were used to estimate average annual health care costs (total costs, those for cardiovascular diseases, and those for cancer). RESULTS: Average annual health care charges were much lower for persons at low risk - the total charges for the men at low risk were less than two thirds of the charges for the men not at low risk ($1,615 less); for the women at low risk, the charges were less than one half of those for the women not at low risk ($1,885 less). Charges related to cardiovascular disease were lower for the low-risk groups of men and women than for those not at low risk (by $979 and $556, respectively), and charges related to cancer were also lower (by $134 and $189). CONCLUSIONS: People with favorable cardiovascular risk profiles in middle age had lower average annual Medicare charges in older age. Having optimal status with respect to major cardiovascular risk factors may result not only in greater longevity but also in lower health care costs.

Adult↗

PubMed1998

Nascent RNA in transcription complexes interacts with CspE, a small protein in E. coli implicated in chromatin condensation.

Proteins in a partially fractionated Escherichia coli extract that interact with the nascent RNA in active transcription complexes from several promoters were detected using the photocrosslinking ribonucleotide analogs 5-(azidophenacyl)thio-UTP or 5-(azidophenacyl)thio-CTP as transcription substrates. Upon irradiation of ternary transcription complexes, several extract proteins were crosslinked to the RNA. Most notably, a small protein was crosslinked to the RNA in complexes on seven of nine templates tested. This protein was purified and sequenced and found to match a hypothetical protein, MsmC/CspE, recently shown to be involved in chromatin partitioning. CspE has 69% amino acid sequence identity with the major cold shock protein in E. coli, CspA, which has been shown to bind to a DNA sequence designated the Y box, with the sequence 5'-ATTGG. Of the nine templates tested, CspE was found to be most heavily crosslinked to RNA from the lambda PR' promoter, which is modified by the Q antiterminator protein. CspE was very heavily crosslinked to RNA only ten nucleotides long in initial ternary complexes on this promoter, but not to this same RNA after it had been released from the transcription complex. However, even when present from the start of transcription, CspE did not crosslink to the RNA 82 nucleotides long in elongation complexes from this same promoter. Despite the loss of interaction with the RNA after polymerase had left the promoter, CspE inhibited Q-mediated transcriptional antitermination from PR' in vitro almost 200 nucleotides downstream from the promoter, presumably by interaction with the Y box DNA upstream from PR', which overlaps with the binding site for the Q. A potential role for CspE and transcription in chromosome condensation and nucleoid structure is discussed.

Amino Acid Sequence↗

PubMed1998

Fine-needle aspiration: comparison of smear, cytospin, and cell block preparations in diagnostic and cost effectiveness.

We compared the results of smears to those of cytospin and cell block preparations from fine-needle aspirations to determine the cost effectiveness of each and to determine which should be routinely obtained. We reviewed 844 cases, 361 of which had both smears and cytospins, and 483 of which had both smears and cell blocks. Smears alone were diagnostic in 94% of cases (796/844 cases), cytospins alone diagnostic in 43% of cases (154/361 cases), and cell blocks alone diagnostic in 57% of cases (277/483 cases). Cytospins contributed additional information beyond that obtained from smears in 2% (7/361) and cell blocks in 12% (57/483) of cases. When smears were nondiagnostic, cytospins contributed additional information in 10% (2/21) of cases and cell blocks contributed additional information in 44% (12/27) of cases. The cost of providing a diagnosis from smear alone is $212, from cytospin alone is $352, and from cell block alone is $392. The cost for additional information established by cytospin is $7,736 and by cell block the cost is $1,906. Smears are superior to either cytospins or cell blocks in providing a diagnosis. It is not cost-effective to obtain either cytospins or cell blocks in addition to smears on all cases. However, it is cost-effective to obtain cell blocks when the immediate smear evaluation is nondiagnostic.

Biopsy, Needle↗